What are the major sources of error in forensic entomology PMI estimates?

• A. PMI estimates rely solely on insect color.
• B. Incorrect species identification, inappropriate developmental data, failure to account for temperature history, and atypical colonization patterns.
• C. Only incorrect species identification.
• D. Entomology is not used for PMI.

Answer: (B)

The major sources of error in forensic entomology PMI estimates come from multiple factors, not a single clue. Inaccurate species identification is a big problem because different species develop at different rates and have distinct life-stage benchmarks; misidentifying the species leads you to apply the wrong growth data. Using inappropriate developmental data compounds that error—development rates must match the exact species and the geographic/population context, since growth can vary with genetics and local climate. Failing to account for temperature history is another key issue: insect development is driven by accumulated heat over time, so ignoring actual temperature exposure, microclimates, or indoor vs. outdoor conditions can skew the estimated age of the insects. Finally, atypical colonization patterns can throw off PMI. If colonization occurs earlier or later than expected due to scene access, disturbances, or scavengers, the assumed timeline used to translate insect age into time since death becomes unreliable.

These interconnected factors explain why the comprehensive answer—encompassing species ID, appropriate developmental data, temperature history, and colonization patterns—best describes the major sources of error.